X-Ray Tomosynthesis Imaging Device and Calibration Method of an X-Ray Tomosynthesis Imaging Device

1. An X-ray imaging device comprising: an X-ray source that is able to move along a predetermined movement path; a movement unit configured to cause the X-ray source to move along the predetermined movement path; an imaging platform that is disposed to face the X-ray source; a flat-panel X-ray detector that is provided to the imaging platform; a marker that is disposed in the imaging platform; a control unit that causes the X-ray source to move via the movement unit and to capture images respectively including the marker from at least two positions; and an image processing unit that calculates a position of an image of the marker in each of the captured images and corrects the each of the captured image using the slope of a movement axis of the X-ray source with respect to the X-ray detector and calculates a slope of a movement axis of the X-ray source with respect to the X-ray detector based on a relative relationship between positions of images of the marker.

2. The X-ray imaging device according to claim 1 , wherein the slope with respect to the X-ray detector is a first slope in a plane parallel to a surface of the X-ray detector.

3. The X-ray imaging device according to claim 1 , wherein the image processing unit further calculates a variation in size of an image of the marker in each of the captured images, calculates a distance between the X-ray source and the X-ray detector using the variation in size, and calculates a second slope in a plane perpendicular to a surface of the X-ray detector as another slope with respect to the X-ray detector.

4. The X-ray imaging device according to claim 1 , wherein the image processing unit calculates the slope with respect to the X-ray detector for each imaging position of the X-ray source.

5. The X-ray imaging device according to claim 1 , wherein the image processing unit has a function of reconstructing a tomographic image using a plurality of images obtained by causing the X-ray source to move to predetermined imaging positions via the movement unit and performing a tomosynthesis imaging operation, and wherein the image processing unit uses the slope with respect to the X-ray detector to reconstruct the tomographic image.

6. A calibration method of an X-ray imaging device including an imaging platform disposed to face an X-ray source that is able to move along a predetermined movement path, a flat-panel X-ray detector provided to the imaging platform, and a marker, the calibration method comprising the steps of: causing the X-ray source to move and to capture images respectively including the marker from at least two positions; and calculating a position of an image of the marker in each of the captured images and calculating a slope of a movement axis of the X-ray source with respect to the X-ray detector based on a relative relationship between positions of images of the marker and corrects the each of the captured image using the slope of a movement axis of the X-ray source with respect to the X-ray detector.

7. The calibration method according to claim 6 , wherein the slope with respect to the X-ray detector is a first slope in a plane parallel to a surface of the X-ray detector.

8. The calibration method according to claim 6 , further comprising a step of calculating a variation in size of the marker image in each of the captured images, calculating a distance between the X-ray source and the X-ray detector using the variation in size, and calculating a second slope in a plane perpendicular to a surface of the X-ray detector as another slope with respect to the X-ray detector.

9. The calibration method according to claim 6 , wherein the slope with respect to the X-ray detector is calculated for each imaging position of the X-ray source.

10. An X-ray tomosynthesis imaging device comprising: an X-ray source that is able to move along a predetermined movement path; a movement unit configured to cause the X-ray source to move along the predetermined movement path; an imaging platform that is disposed to face the X-ray source; a flat-panel X-ray detector that is provided to the imaging platform; a marker that is disposed in the imaging platform; a control unit that causes the X-ray source to move via the movement unit and to capture a plurality of first images respectively including the marker from a plurality of different positions and causes the X-ray source to move via the movement unit to a predetermined plurality of imaging positions via the movement unit to perform a tomosynthesis imaging operation and capture a plurality of second images by; a storage unit that stores existing calibration data; a calibration unit that performs a calibrating operation on a misalignment in a movement direction of the X-ray source disposed to face the X-ray detector; and calculates a position of an image of the marker in each of the captured the plurality of the first images, and creates first calibration data based on a relative relationship between positions of images of the marker; a determination unit that determines whether to update the existing calibration data stored in the storage unit to the first calibration data based on a position of an image of the marker in each of the captured the plurality of the first images, a reconstruction unit that, when update is negative by the determination unit, reconstructs a tomographic image using the existing calibration data and the plurality of the second images, and, when update is positive by the determination unit, reconstructs a tomographic image using the first calibration data and the plurality of the second images.

11. The X-ray tomosynthesis imaging device according to claim 10 , wherein the determination unit determines whether to update the calibration data based on a position of the first image of the marker and a position of the second image of the marker, the first image and the second image being two images in the plurality of the first images and determines whether to update the calibration data based on a misalignment between the position of the image of the marker in the second image and the position of the corresponding marker image which corresponds to the image of the marker in the second image.

12. The X-ray tomosynthesis imaging device according to claim 10 , wherein the calibration unit calculates a first slope of a movement axis of the X-ray source in a plane parallel to the surface of the X-ray detector based on a relative relationship between a position of the image of the marker in the first image and a position of the image of the marker in the second image, and creates the first calibration data based on the first slope, and wherein the first image and the second image are two images in the plurality of the first images.

13. The X-ray tomosynthesis imaging device according to claim 10 , wherein the calibration unit calculates at least one variation in size of an image of the marker of the plurality of the first images, calculates a distance between the X-ray source and the X-ray detector using the variation in size, calculates a second slope of the X-ray source in a plane perpendicular a the surface of the X-ray detector, and creates second calibration data based on the second slope.

14. The X-ray imaging device according to claim 12 , wherein the calibration unit calculates at least the first calibration data out of the first calibration data and the second calibration data for each imaging position of the X-ray source.

15. The X-ray imaging device according to claim 13 , further comprising a reconstruction unit that reconstructs a tomographic image using a plurality of images obtained by causing the X-ray source to move to predetermined imaging positions via the movement unit and performing a tomosynthesis imaging operation, wherein the reconstruction unit uses at least the first calibration data out of the first calibration data and the second calibration data to reconstruct the tomographic image using the plurality of images captured through the tomosynthesis imaging operation.

16. A calibration method of an X-ray tomosynthesis imaging device including an imaging platform disposed to face an X-ray source that is able to move along a predetermined movement path, a flat-panel X-ray detector provided to the imaging platform, and a marker, the calibration method comprising the steps of: causing the X-ray source to move to capture a plurality of first images respectively including the marker from a plurality of different positions; causing the X-ray source to move to a plurality of predetermined imaging positions and perform a tomosynthesis imaging operation to capture a plurality of second images; calculating a position of an image of the marker in each of the plurality of the first images captured, and creating first calibration data based on a relative relationship between positions of images of the marker, determining whether to update the existing calibration data based on a position of an image of the marker in each of the plurality of the first images captured, and when update is rejected, reconstructing a tomographic image using the existing calibration data and the plurality of the second images, and, when update is approved, reconstructing a tomographic image using the first calibration data and the plurality of the second images.

17. The calibration method of an X-ray tomosynthesis imaging device according to claim 16 , wherein the step of performing the calibration includes steps of: determines whether to update the calibration data based on a position of the first image of the marker and the position of the second image, the first image and the second image being two images in the plurality of the first images; calculating a position of a corresponding marker image which corresponds to the image of the marker in the second image from the position of the image of the marker in the first image using existing calibration data; and determining whether to update the calibration data based on a misalignment between the position of the image of the marker in the second image and the position of the corresponding marker image which corresponds to the image of the marker in the second image.

18. The calibration method of an X-ray tomosynthesis imaging device according to claim 16 , wherein the step of performing the calibration includes steps of: calculating a first slope of a movement axis of the X-ray source in a plane parallel to a surface of the X-ray detector based on a relative relationship between a position of images of the marker in the first image and a position of images of the marker in the second image; and creating the first calibration data based on the first slope, the first image and the second image being two images in the plurality of the first images.

19. The calibration method an X-ray tomosynthesis imaging device according to claim 16 , wherein the steps of calculating at least one variation in size of an image of the marker of the plurality of the first images, calculates a distance between the X-ray source and the X-ray detector using the variation in size, calculates a second slope of the X-ray source in a plane perpendicular to a surface of the X-ray detector, and creates second calibration data based on the second slope.